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RSC Advances
Page 4 of 5
DOI: 10.1039/C5RA11285K
COMMUNICATION
Journal Name
Another advantage of the SnO2/RGO nanocomposite is the
robust reusability, which is a prerequisite for practical applications.
After the reaction, the solid catalyst was separated from the
reaction mixture conveniently by simple filtration. The recyclability
was then tested under the identical conditions through the
epoxidation of cyclohexene. The results in Fig. 4 demonstrated that
the heterogeneous catalyst was fairly stable for ten cycles without
observing significant decrease in catalytic activity. Both conversion
and selectivity were still higher than 90% throughout ten runs. The
robust recyclability of SnO2/RGO nanocomposite may originate
from the strong interactions between graphene and metal oxide.
Evidence for the stability of our catalyst can be seen in further
tests. The XRD patterns of the fresh and the reused one (after 10
recycles) are shown in Fig. S6. Obviously, there is no discriminable
difference between the fresh catalyst and the spent one, indicating
that the characteristic peaks of tetragonal SnO2 still exist. The TEM
image of the recovered catalyst (Fig. S7) further confirmed that the
size of SnO2 is still around 3nm intuitively after ten recycles,
suggesting that graphene prevent the aggregation problem
efficiently. The result of ICP-AES analysis showed no trace of Sn in
the filtrate, which is also confirmed by the TG curves (Fig. S8), as the
amount of active spieces remained at 77% in consecutive cycles.
These results infer that the nanocomposite is truly heterogeneous
with no active spieces leaching.
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Acknowledgements
Adv., 2014,
4, 11732-11739.
This work was supported by the NSFC (No: 21176213), and Zhejiang
Key Innovation Team of Green Pharmaceutical Technology (No:
2010R50043).
4 | J. Name., 2012, 00, 1-3
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